Producing metallic incandescent bodies for electric glow-lamps.



To itmcy concern: 7 ,Be t known that, I, FRI'rz BLAU, chemist oentBo dies. for Electric Glow-Lamps, and do-hereby declare the following to be a full,

UNIT D STATES FRrrz shiny,

PATENT omuon.

or BEBLIN,-GEBMANY, ASSIGNOR TO DEUTSCHE GASGLUHLICHT AKTIEN- GESELILSQEAFT (AUERGESELLSGHAFT), or BERLIN, GERMANY.

PROD CING METALLIC 'mcANnEscENr non Ins non ELECTRIC GLOW-LAMPS.

4 Specification of Letters Patent. 1 ap l cation filed-June 26, 1906. Serial No. 323,532.

Patented March 30, 1909.

a subject of the Emperor of Austria-Hun gary, and a resldent of. Berlin, Germany,

, have invented certain .new and 'useful Improv'ements in ProducingMetallic Incandesclear, exact description of the invention, such as w1l1 enable others skilled in the art to WhlGh "1t appertams to make] and use the My invention relates to an improved method. of reducing; metallic incandescence bodies for e ectric glow lamps.

This inve 'tion relates to the production of .metallic electric incandescence bodies such as the metallic filaments of electric glow lamps particularly. those of tungsten prepared by eating the crude filaments to white heat in anatmosphere that will not attack the final 1 product. I This heating is effected in order to niake the individual particles of the incandescen'ce'bodysinter together as completely as. possible, so as to prevent any further change in the diniensions of the filament or its resistance when the lamp is used; The

0 ration of heat g to whiteness is prefera ly performedir ta gas consisting of, a mixless, are produced. These deformations as'-. singled-very serious proportions until I found 7 1 of r gemand hydrogen.

being-inert relatively to the final product,

ideralole inconven'a This gas,

will not attack it. fence is produced thereby,-however, especially with the very thin filaments, as irregular deformations of an extensive nature, often makingthe incandescence body qulte usethat they were due to the use of an alternat- .ing current, a current of this kind, with a frequency of about fifty alternations per second having been available and used at first. Alternating current was then replaced by a continuous or direct current, with the result that such irregular deformations ceased to ternat'ing current, in its action on the filaments in course of manufacture, and the applicationof a continuous or direct current to the process of sintering at white heat is accompanied by great technical advantages. According to the present invention, therefore, the said sintering process is effected by means of a continuous or direct current, instead of by the apparently equivalent alternating current, in order to obviate the irregular deformations occurring with the latter.

I claim as new and desire to secure by Letters Patent of the United States of America is A method of producing metallic incandescence bodies for electric glow lamps, consisting in sintering the crude filaments in a gas inert relatively to the final products, at a stantially as and for-the purpose described. In testimony that I- claim the foregoing as y invention, I have signed my name in presence of two subscribing witnesses.

FRITZ BLAU.

Witnesses WOLDEMAR HAUPT,

HENRY HASPER.

Having thus described my invention, what white heat obtained by passing a continuous" or direct current through such bodies sub-.

occur at all. A difference consequently v exlsts between continuous or direct and alv 

